User`s manual

UC-7400-LX Plus User’s Manual Managing Communications
4-6
The UC-7400-LX Plus supports the following sub-modules. Be sure to use the module that
matches your application.
ip_conntrack ipt_MARK ipt_ah ipt_state
ip_conntrack_ftp ipt_MASQUERADE ipt_esp ipt_tcpmss
ipt_conntrack_irc ipt_LOG ipt_length ipt_tos
ip_nat_ftp ipt_REDIRECT ipt_limit ipt_ttl
ip_nat_irc ipt_REJECT ipt_mac iptable_mangle
ip_nat_snmp_basic ipt_TCPMSS ipt_mark iptable_nat
ip_queue ipt_TOS ipt_multiport iptable_filter
ipt_LOG ipt_ULOG ipt_owner ip_tables
NOTE
The UC-7400-LX Plus does NOT support IPV6 and ipchains.
The basic syntax to enable and load an IPTABLES module is as follows:
#lsmod
#modprobe ip_tables
#modprobe iptable_filter
Use lsmod to check if the ip_tables module has already been loaded in the UC-7400-LX Plus. Use
modprobe to insert and enable the module.
Use the following command to load the modules (iptable_filter, iptable_mangle, iptable_nat):
#modprobe iptable_filter
Use iptables iptables-restore and iptables-save to maintain the database.
NOTE
IPTABLES plays the role of packet filtering or NAT. Take care when setting up the IPTABLES
rules. If the rules are not correct, remote hosts that connect through a LAN or PPP may be denied
access. We recommend using the serial console to set up the IPTABLES.
Click on the following links for more information about iptables.
http://www.linuxguruz.com/iptables/
http://www.netfilter.org/documentation/
HOWTO//packet-filtering-HOWTO.html
Since the IPTABLES command is very complex, to illustrate the IPTABLES syntax we have
divided our discussion of the various rules into three categories: Observe and erase chain rules,
Define policy rules, and Append or delete rules.
Observe and erase chain rules
Usage:
# iptables [-t tables] [-L] [-n]
-t tables: Table to manipulate (default: ‘filter’); example: nat or filter.
-L [chain]: List List all rules in selected chains. If no chain is selected, all chains are listed.
-n: Numeric output of addresses and ports.
# iptables [-t tables] [-FXZ]
-F: Flush the selected chain (all the chains in the table if none is listed).
-X: Delete the specified user-defined chain.
-Z: Set the packet and byte counters in all chains to zero.